driver, cppdefault: Unbreak bootstrap on Debian/Ubuntu [PR107059]
My recent change to enable _Float{16,32,64,128,32x,64x,128x} for C++
apparently broke bootstrap on some Debian/Ubuntu setups.
Those multiarch targets put some headers into
/usr/include/x86_64-linux-gnu/bits/ etc. subdirectory instead of
/usr/include/bits/.
This is handled by
/* /usr/include comes dead last. */
{ NATIVE_SYSTEM_HEADER_DIR, NATIVE_SYSTEM_HEADER_COMPONENT, 0, 0, 1, 2 },
{ NATIVE_SYSTEM_HEADER_DIR, NATIVE_SYSTEM_HEADER_COMPONENT, 0, 0, 1, 0 },
in cppdefault.cc, where the 2 in the last element of the first initializer
means the entry is ignored on non-multiarch and suffixed by the multiarch
dir otherwise, so installed gcc has search path like:
/home/jakub/gcc/obj01inst/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/13.0.0/include
/home/jakub/gcc/obj01inst/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/13.0.0/include-fixed
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
(when installed with DESTDIR=/home/jakub/gcc/obj01inst).
Now, when fixincludes is run, it is processing the whole /usr/include dir
and all its subdirectories, so floatn{,-common.h} actually go into
.../include-fixed/x86_64-linux-gnu/bits/floatn{,-common.h}
because that is where they appear in /usr/include too.
In some setups, /usr/include also contains /usr/include/bits -> x86_64-linux-gnu/bits
symlink and after the r13-2896 tweak it works.
In other setups there is no /usr/include/bits symlink and when one
#include <bits/floatn.h>
given the above search path, it doesn't find the fixincluded header,
as
/home/jakub/gcc/obj01inst/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/13.0.0/include-fixed/bits/floatn.h
doesn't exist and
/home/jakub/gcc/obj01inst/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/13.0.0/include-fixed/x86_64-linux-gnu/bits/floatn.h
isn't searched and so
/usr/include/x86_64-linux-gnu/bits/floatn.h
wins and we fail because of typedef whatever _Float128; and similar.
The following patch ought to fix this. The first hunk by arranging that
the installed search path actually looks like:
/home/jakub/gcc/obj01inst/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/13.0.0/include
/home/jakub/gcc/obj01inst/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/13.0.0/include-fixed/x86_64-linux-gnu
/home/jakub/gcc/obj01inst/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/13.0.0/include-fixed
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
and thus for include-fixed it treats it the same as /usr/include.
The second FIXED_INCLUDE_DIR entry there is:
{ FIXED_INCLUDE_DIR, "GCC", 0, 0, 0,
/* A multilib suffix needs adding if different multilibs use
different headers. */
#ifdef SYSROOT_HEADERS_SUFFIX_SPEC
1
#else
0
#endif
},
where SYSROOT_HEADERS_SUFFIX_SPEC is defined only on vxworks or mips*-mti-linux
and arranges for multilib path to be appended there. Neither of those
systems is multiarch.
This isn't enough, because when using the -B option, the driver adds
-isystem .../include-fixed in another place, so the second hunk modifies
that spot the same.
/home/jakub/gcc/obj01/gcc/xgcc -B /home/jakub/gcc/obj01/gcc/
then has search path:
/home/jakub/gcc/obj01/gcc/include
/home/jakub/gcc/obj01/gcc/include-fixed/x86_64-linux-gnu
/home/jakub/gcc/obj01/gcc/include-fixed
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
which again is what I think we want to achieve.
2022-09-29 Jakub Jelinek <jakub@redhat.com>
PR bootstrap/107059
* cppdefault.cc (cpp_include_defaults): If SYSROOT_HEADERS_SUFFIX_SPEC
isn't defined, add FIXED_INCLUDE_DIR entry with multilib flag 2
before FIXED_INCLUDE_DIR entry with multilib flag 0.
* gcc.cc (do_spec_1): If multiarch_dir, add
include-fixed/multiarch_dir paths before include-fixed paths.